| 摘要 |
A mode division multiplexing passive optical network (PON) in which channel estimation/inversion is performed in the optical domain. The PON comprises a plurality of input channels 308 connected to a mode multiplexer 318, a mode demultiplexer 312 connected to a plurality of output channels 314 and an optical fibre coupling the multiplexer and the demultiplexer for transporting a mode-multiplexed signal. The PON includes an optical equalizer 318, 316 arranged to transfer power between optical signals having different modes to compensate for crosstalk between the different modes. The optical equalizer 316 may be positioned downstream of the demultiplexer and a second optical equalizer 318 may optionally be positioned upstream of the multiplexer. In a preferred embodiment, equalization need only take account of interference between degenerate modes. |
